Research On Fault Location Method Of Distribution Network Based On Fault Indicator System

Distribution network has complex structure,wide distribution of branch lines and high cost of line patrol.It is of great practical significance to improve the accuracy and accuracy of fault location in distribution network.Most of the existing fault location methods need to measure zero-sequence current,zero-sequence voltage or compare the calculation results of each outgoing line.They can only select the line in the substation.Based on the fault indicator system,this paper can locate the fault point between two groups of adjacent fault indicators and locate the fault section directly,which has better location accuracy.Single-phase grounding fault accounts for the vast majority of distribution network faults,and its fault characteristics are not obvious,which affects the accuracy of fault location of fault indicator system.Therefore,the signal injection method is used to inject the controlled disturbance current with obvious characteristics into the fault line,which is convenient for fault indicator detection and improves the accuracy of fault indicator system location.Distribution network structure is complex and the working environment on site is bad.Fault indicator system will inevitably lead to false alarm or missed alarm due to communication interruption or its own reasons.Therefore,fault indicator system should have certain fault tolerance.In this paper,the artificial intelligence algorithm is used to locate the fault section accurately when the fault indicator fails to report or missing report.When the line is complex and there are many line faults,artificial intelligence algorithm can quickly determine the fault section,which is more efficient than manual judgment.The installation standard of fault indicator in Yunnan Province is a set of 3 km,that is,the positioning accuracy of fault indicator system is 3 km.Based on the principle of impedance location,this paper introduces the secondary location algorithm,and combines the principle of pseudo fault point removal.The location accuracy of inter-phase short circuit fault can reach 1 km without additional hardware equipment.The main contents of this paper are as follows:(1)The structure and working principle of the fault indicator system are analyzed,and its installation and distribution in Yunnan Province are investigated.The signal injection method is introduced to improve the positioning accuracy of the fault indicator system,and the feasibility of the signal injection method is verified by a case.(2)In order to improve the fault tolerance of fault indicator system,artificial fish swarm algorithm and grey wolf optimization algorithm are used.Firstly,the algorithm is improved to be suitable for fault location in distribution network.Then the two algorithms are compared with particle swarm optimization through case analysis.Finally,the fault location effects of the three algorithms are compared and analyzed.(3)In order to further improve the accuracy of fault location for inter-phase short circuit,the principle of impedance method is analyzed and the fault types are identified.Secondly,the fault point is located by one-time location algorithm.When there is branch load before the fault point,the result of one-time location is corrected by using twotime location algorithm combined with line topology structure.Finally,the feasibility and accuracy of the secondary location algorithm are checked through case analysis,and the false fault points are eliminated according to the action of the fault indicator on the line.Through case analysis,the methods mentioned above are feasible,and have certain theoretical basis and practical value.